Pen



FIG. 1 is a front perspective view of a pen showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is right side elevational view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a front perspective view thereof in an exploded condition. 

The ornamental design for a pen, as shown and described. 